// MP5 Round
gSkillData.plrDmgMP5 = GetSkillCvar( "sk_plr_9mmAR_bullet");
This is what I found. If the damage value is indeed initiated here - well its not in the programming sdk persay.. Cvar's are generally stored in txt files with appropriate values. Id say theres a .cfg file with damage values listed nex to the appropriate cvar. Which is loaded when the game starts up. This is how quake works. You may have to search through a PAK file for the needed file.
However there is away around this. Add a new console command or piggy back some pre defined function so that the value of dmg is printed into the console. IE. That will tell you what the value is. After that you can do a cheap trick - find all the instances where the member variable of the struct is used in a multiplyer for damage - and replace it with your own value.